Rotary drum



May lo, 1932 K. E. E. HoLzAPFEL 1,857,785

ROTARY DRUM Filed may s, 195o 2 sheets-sheet 1 K lll-Iff,

INVENTOR BY@ f 6 /N ATTORNEY A May 10, 1932 n K. E, E. HoLzAPFE-l. 1,857,785

ROTARY DRUM Filed May s, 19:50 2 sheets-sheet 2 Patented May l 10, 1932 UNITED` jsTATss PATE NT OFFICE; i

KARL ERNST EBERHARDT HOLZAPFEL, F MNSTER. GERMANY, ASSIGNOB i KRUPP GRUSON'WERK A. G., 0F MAGDEBURG-BUCKAU, GERMANY, .A CORPORATION 0F GERMANY Application led Hay 3, 1930, Serial No.

This invention relates to rotary drums or kilns of the kind commonly employed for burning lime, slurry for the production of cement and for other materials of a similar' character, as Well as lfor drying ores of various kinds, and theinvention has for its object the rovision of an improved rotary drum of this kind.

More particularly, the invention is concerned with the provision within a rotary drum of an arrangement ofchains, disposed in diiierent ways in different portions or zones of the drum, some of the chains being tensely stretched across the interior of the drum, While others are arranged to hang loosely from one end or are arranged to have slack portions intermediate their ends. Through thev provision of a considerable number of chains arranged differently for different specific operations, 'the material which passes through the drum from the feedin end to thc discharge end thereof, is treate more thoroughly, efiiciently and uniformly. i

In the burning of material such as slurry, it is especially important to have an arrangement of devices adapted effectively to operate upon the changing ph sical conditions of the slurry during the r ing thereof. The devices to this end shou d have various functions; in some instances acting to retard the advancing movement of the slurry, in other instances to whirl it about, in others to loosen and disintegrate it, in still others to accelerate its advancing movement longitudinall of the drum, and at all times to' vincrease tie surface exposed to the hot gases 7 of combustion.

In ca ing out m improvements. the chains which are tense y stretched as chainlike curtains across the cross sectional area of lthe drum, retard the movement of the: ma-

4their movement with the drum, and these chains stir or churn the material in the drum, preventing sticking of the material to the ROTARY DRUM 449,380, and in Germany Hay 6, 1929.

wall of the drum as well as the cohesion of masses of materlal. Such chains also promote drying by effecting a great increase Y -masses of the material and to effect the dislar mesh attached at intervalsto the inte'-v 'l rior Wall of the drum so that as the drum rotates, to alternate in dangling in the interior of the drum and in forming aybalrier at thelowest part of the drum wherebytemporarily to retard the advancing movement of the material longitudinally of the drum. y"In order to increase the whirling effect, I may employ-.interconnecting chains between the tensely stretched chains, or between the slack` chains, or between both of such kinds of chains. lVith the interconnecting chain arrangement, rI can stir up the material and at the same time distribute it transversely across the cross sectional area of the drum.

In someV instances, Where at certain zones it 'is f desired tomove the material more rapid :y toward the burning zone, I arran e the Xed or. attaching parts'for the chalns in circular or helical series on the concave Wall I l forth, of a num r ofl further special improvemeiits of various kinds, the purpose and object of which are to improve in a practical Way the construction of means for discontemplate the rovision, as `hereinafter set tributing the material acrossthe cross sectional area ofthe drum and as well' for effecting uniform and rapid heating and'drying of the material. i

For a full understanding of my improvements, reference is to be had to the accompanying drawings, forming a material part of this application. and in which:

Figure 1 represents a fragmentaly longitudinal section through a rotary rum or kiln equipped in different zones with the different chain arrangements;

Fig. 2 is a cross section taken on the line 2,-2 of Fig. 1; v

Fig. 3 is a cross section taken on the line 3-3 of Fig. l;

Fig. 4 is a cross section taken on the line 4 4 of 1; and

Fig. .5 represents an elevation and section of a drying drum equipped with my improved arrangement of chains.

Referring to the drawings and more particularly to Figs. 1 to 4, inclusive, I shall by way of example particularly describe my invention as applied to a longitudinally inclined rotar drum or kiln 10 of a well-known type, but it 1s to be understood in this connection that my improvements are not limited in their application to such particular type of drum or kiln inasmuch as the improvements herein illustrated may be employed to advantage in many different types of rotary drum structures, whether used both for drymg and vburning material7 or in the capacity of a i" dryer alone.

The drum or kiln is mounted for rotation in any known or approved manner and it may be slowly rotated in the usual way by means of a driving pinion 11 opera-tively engaged with an externally toothed ring 12 surrounding the drum as shown. The feeding or elevated end of the drum may be arranged in well-known manner to have turning movement in the wall of a housing 13 constructed and arranged to provide a smoke or dust box 14 for receiving the combustion gases from the open end 15 of the drum. The slurr or other material is introduced into the fee ing end of the drum by means of a feed pipe 16. Associated with the lower or delivery end of the drum is a movable structure 17 carrying a burner 18 of any known or approved ty Themovable structure is adjusted to the elivery end of the drum so that the burner will enter therein as shown to provide the flame 19 in the position desired in the burning zone of the drum. l

As represented in the drawings, I secur to the inner wall of the rotary drum 10, at or near the end of the effective drying zone, the opposite ends of chains 20 by means of suitable hooks 21 riveted or otherwise secured in the wall of the drum. Said chains 20 are tensely ortautly ystretched and preferably, as shown, they are arranged side by side so as to form a complete screen curtain or wall extending across the entire cross sectional area of the drum. In close adj acency to the chains 20 another curtain or Wall of chains 22 is arranged, the chains thereof also being tensely or tautly stretched across the drum, but in a direction different from the chains20 of the rst curtain. As best shown in Fig. 2, the

' axis of the drum and supported by radial arms 26, secured fortheir support to the wall of the drum. Some of the radially stretched chains 23, intermediate.their length, are connectedby cross chains 27. The chains 23 and 27, so arranged and connected, form a helically shaped net extending longitudinally along the drying zone or section of the drum and closely adjacent to the chain curtains or walls 20 and 22. The helically shaped net of chains, as the drum rotates, dips into the material at the lowest partfof the drum, raises the material and distributes it through the cross sectional area of the drum, and at the same time and more particularly conveys or advances the material toward the chain curtains which operate to keep back the material until it is thoroughly dried and in a proper condition to sift through the chain curtains for treatment in the burning zone proper. In the accompanying drawings, the reference numeral 28 indicates by way of example the height of a mass of material held back by the chain curtains until thoroughly dried, while the reference numeral 29, indicates the material that has sifted through the chain curtains for delivery into the burning zone proper.

Further along toward the feeding end of thedrum is located a group of chains 30, suspended by their ends in a loose or slack condition so as to swing or tumble about as the drum revolves. These chains may be attached to the wall of the drum by hooks 3l or any suitable attaching means; and, manifestly, there may be as many of these chains as desired. These chains lift thematerial from the lowest part of the drum and scatter it through the cross sectional area of the interior of the drum, and at the same time they slide, scrape and knock against the wall of the drum to prevent the sticking or accumulation of the material.

Further on toward the feeding end is a series of loosely hanging short chains 32. In some instances these chains are represented as hanging in pairs; and. it will be evident that, where desired, a group of such chains may be similarly arranged to hang from one end at one point. Some of these'chains are represented as having weights 33 attached to the free ends thereof. These chains. with also hammer upon the neighboring chains and clean the same. Additionally, these chains serve as means for taking up material from the lowest part of the drum. Preced ing these short chains is a double wall of chain curtains 34 and 35 similar to the chain curtains 2O and 22 hereinbeforc described. The purpose and object of the chain curtains 34 and 35 are to hold back the material, which in the case of slurry is at this point of the treatment quite pasty and, therefore, in order to obtain the best resultsrequires retardation and distribution until thc material has given up much of its moisture.

Preceding these chain curtains is, by preference, another group of loosely hanging short chains 36, some of which at least may be equipped with Weights. These short chains have the same function as the short chains 32; and both of these groups of chains hammer upon neighboring chains in order to remove adhering material.

Further along toward the feeding end of the drum is a 'chain mesh arrangement consisting of a number of circularly arranged chains 37, hanging in spaced relation, each being connected to the inner wall of the drum by a circular series of anchoring devices or lugs 38. These chains at suitable intervals are connected one with another by short cross chains 39. This chain mesh arrangement not only takes up material for distribution throughout the cross sectional area of the drum, but the slackly held segments of the chains in conjunction with the connecting cross members slide. scrape and hammer on the drumand on each other, thereby continuously mixing and iiinging the pasty material for exposure to the hot gases of combustion.

40 designates another group of chains which, by preference, have limited flexibility, being fixed at their opposite ends so as to have a more or less degree of slackness between their ends. For these chains the attachin hooks 41 are arranged in circular or hellcal series or lines.

These chains, as shown inthe drawings, are attached so as to have oblique inclination for the purpose of acting as a screw to feed the material. which enters through the supply pipe 16. from the open end 15 of the drum and toward the chain mesh arrangement. These feed chains churn up the freshly introduced material and hasten the conveyance ofthe same toward the chain mesh arrangement.

Briefly stated, the operation of my invention is as follows: The material to be dried or burned is introduced -into the drum through the supply pipe 16. The drum revolving in the usual Way, conveys the material toward the discharge end thereof. The heating gases, moving in a counter direction toward the open end l5 of the drum, dry and burn the material. As previously stated. the

helically arranged chains 40 canse the material to move longitudinally with increased speed to the chain mesh arrangement 37 by which the material is lifted and distributed. The chain curtains 34 and35 hold back the advancing movement of the pasty material While the intervening short chains 36, with and Wit-hout Weights, have a hammering action both upon the chain mesh 37 and upon the Vadjacent chain curtain 35. The chain portions are promptly hammered olf and disintegrated by the .slack chains and especially by the Weights carried by such chains.

As the material is spread, flung about and sifted by the action of the chains, there is a great increase in the surfaces of the material exposed to the hot exhaust gases so that the material is rapidly heated and dried. The

material. therefore. isquite dry as it advances to the effective drying zone Where it is acted upon by the helical group of chains 23 Awhich operateto increase the advancing movement of the material and at the same time to distribute an'd Whirl the material about. `The chain curtains or Walls 22 and 2() cause, as before explained, a temporary stowage of the material over the entire zone provided with these chains, which move in a bath of material, as one might say, and these chains have at all times, owing to their retarding action, plenty of material to act upon for whirling and distributing. All of the chains, even los' those which accelerate the advance of the material longitudinally of the drum, have of course a more or less retarding action upon the material, since in being distributed and flug about, the material is caused to travel longer distances.

Referring to Fi g. 5, Where another selected embodiment of my invention has been illustrated, 42 designates a drying drum which is mounted for rotation in any suitable or approved manner. In the present instance the drum is slowly rotated by means of a driving pinion 43 which is engaged with an externally toothed ring 44. The elevated or feeding end of the drum is herein represented as having 1 turning movement in the end Wall of a housing 45 constructed and arranged to provide a lsmoke or dust chamber 46 which in practice may be in communication with a suitable flue or the like. The material is introduced into the drum through a suitable supply pipe or hopper 47. Associated with the lower or discharge vend of the drum is a furnace structure 48 provided with the usual fire grate 49 whereon the material is burned for supplying j. ing' drum is represented as provided. with ',groups of chains ot' the same kind and 1n the A saine arrangement as illustrated in Fig. 1

herein. Thus there is a helical group 51 corresponding to the helicalgroup 23; a slac group 52 corresponding with the slack group 30; a shortchain group 53 corresponding with the short chain group 32; chain walls 54 and 55 corresponding respectively with the chain Walls 34 and 35; a short chain group 56 corresponding with the'short chain group 36; a corresponding chain mesh arrangement 57 and `also corresponding feeding chains 58. In'front of the helical group 51 there may also be provided suitable chain curtains as 22 and 20, as shown inl Fig.. 1. These chains are shown in connection with the drying drum for purposes of illustration f only, and in practice, they may be `arranged in a different order or series.

The invention, of course, is not limited to the. particular disposition of the var ious classes of chains illustrated and described herein, and the chains of the dilierent classes may be arranged in any suitable or etiicient manner for temporarily stowing or retarding the material, for taking itup and distributing it, and as well for cleaning the walls of the drinn and for cleaning the chains themselves, and in addition for causing an accelerationA in the advance of the material toward the discharge end thereof. The chains may differ in nui-uber and also in form as may be necessary in order to obtain the best results in accordance with the character of the material which is to be treated in the drum. The chains may also ditler in caliber or in protile, as in practice found necessary in order best to meet the various special conditions encountered in the treatment of the material in a burning or drying drum. The different single chain groups may be arranged in differentI orders of succession and still be Within the scope of the invention.

lVhile the invention has been illustrated and described with some degree of particularity. it is realized that in practice various changes and alterations may be made therein, and further that the invention is capable of embodiment in many different types of rotary drums.

It has been sought herein to illustrate such embodiments as will suffice to exhibit the character of the invention. Reservation is. therefore, made tothe right and privilege of changing the form of details of construction or otherwise altering the arrangement ofthe parts without departing from the spirit or the scope of the invention or the scope of the appended claims.

verse relation, sai( groups of members to-l gether comprising a sieve-like structure revolving with the drum for twirling and sifting the material advanced along the drum and which -also serves to retard the advance of the material, producing an accumulation thereof for the twirli'ng and sifting operations performed by said structure.

2. A revolving kiln drum having, with a longitudinally extending vinterior chamber in which the material under treatment is caused to advance lengthwise of the drum by the operation of the drum, groups of chain memv bers arranged in adjacent planes and extending across the interior chamber, the members of the group in 'each plane being substantially parallel and the members of the groups in ad]acent cplanes extending in transverse relation, sai groups of members together comprising a sieve-like structure revolving with the drum for twirling and sifting the material advanced along the drum., and means com' rising an arrangement of chains. located at tie feeding side of said structure and operating With the drum to churn up and distribute the advancing material against said structure by means of which the material is sifted. l I

3. A revolving kiln drum having. with a longitudinally extending interior chamber in which the material under treatment is caused toadvance lengthwise of rthe drum by the operation of the drum. chain members stretched across the chamber in groups in adpicent planes. the members in each plane being substantially parallel and the members in adjacent planes extending in transverse relation, said groups of members together comprising a` sieve-like structure revolving with the drum for twirling and sifting the material and which retards the advancement of the material, producing an accumulation in the feeding zone before the structure. and means for accelerating the advancement of the accumulation againstsaid structure. comprising groups of chains turning with thev drum and the members of which are disposed around the concave Wall of the drum in amanner to produce the effect of a screw convevor adapted to churn up, distribute and advance the material against said structure by means of which the material is sifted.

4. A revolving kiln drum having, vwith a longitudinally extending interior feeding ios lll

zone in which the material under treatment is caused to atlvanee lengthwise of the drum by the operation of the drum, groups of chain members arranged in adjacent planes across 5 the feeding zone. the members of the group in each plane being substantially parallel and the members of the groups in adjacent planes extendingv in transverse relation t0 each other, said groups of members comprising a sievel0 like structure revolving with the drum for twirlinfgr and siftingr the material received from the feeding1r zone.l and means eomprising chains, positioned in the feeding zone and operating.,r with the drum to churn up and clis- 15 tribute tlle'material towards said structure b means of which the material is siftethinclu ing chains stretched in a tense condition, chains which are slack to have swinging movement and chains dangling from one end 20 to hammer on the wall of the drum and against other of the cha-ins.

In testimony that I claim the foregoing as my invention, I have signed my name hereto.

Dr. KARL ERNST EBERHARDT HOLZAPFEL. 

